Download Biodiversity Notes

Important Terms
 Biodiversity: The
amount of different
species living in an area.
 Genetic Diversity:
Different genetic
characteristics of a
species.
Cheetah populations have
very low diversity, due to
inbreeding
Important Terms
 Species Diversity:
The number of species or
organisms per unit area
found in different habitats
of the planet.
Important Terms
 Habitat Diversity: The amount of habitats or niches in a
given area
 Variety of forests, deserts, grasslands, lakes, oceans,
coral reefs, wet lands, and other biological communities.
Chaparral
Coniferous forest
dessert
grasslands
deciduous forest
Biodiversity: Why should we care?
 Diverse ecosystems are more stable and more healthy
 More resistant to damage from factors like climate
change and spread of disease
 Provides important ecological services to humans
 Biodiversity is useful to us as humans
 Recreation
 Food
 Goods
 Medicine
Pre-Assessment Questions
(Write on Loose leaf paper)
 How do you think diversity changes during succession?
 Do you think a more complex ecosystem is more or
less stable?
 How could human activities (agriculture, mining…)
impact biodiversity?
 What are the potential positive and negative results of
human activities that reduce diversity?
 How might habitat diversity impact species diversity
and genetic diversity?
Ecological Services of
Biodiversity
 Flow of material, energy in
the biosphere
 Photosynthesis
 Pollination
 Soil formation and
maintenance
 Nutrient cycling
 Moderation of weather
extremes
 Purification of air and water
Important “stuff” From biodiversity
 Food, fuel, ecosystems, species, fiber, lumber, paper….
 90% of all food crops
 40% of all medicines and 85% of all antibiotics
Pacific Yew – Taxol
(cancer drug)
Willow Tree - Aspirin
Biodiversity of Species
Darwin Natural Selection
 Important Terms
 Evolution: A change in the gene
pool of a population over time
 Natural Selection: Process by
which individuals that are better
suited to their environment
survive and reproduce more
successfully.
 Adaptation: An inherited
characteristic that increases an
organism’s chance of survival.
Darwin's
Research
 Studies 13 species of finches
on Galapagos Islands
 Looked a beak size and shape:
 Stout beaks for eating seeds
 Short and sharp beaks for
eating insects.
 Woodpecker-like beak for
eating insects from trees, but
instead of a long tongue it
uses a cactus spine held in its
beak to remove its prey.
Darwin’s Finches
Darwin’s Theory
 Based on his observations he proposed
that the evolution of species occurs by
Natural selection.
 Occurred due to:
 Variation within populations (Genetic
Diversity)
 Overproduction of offspring (J and S
curves)
 Struggle for existence (Competition/
Limited resources)
 Unequal survival and reproduction rates
(R and K)
Population of Organisms
Overproduction of Offspring
Mutations & Sexual Reproduction produces
variations among offspring.
Limited resources leads to a
struggle for survival between
offspring.
Survivors reproduce more
successfully.
Population changes over time.
What is a species?
 Species: A group of interbreeding populations, with a
common gene pool, which are reproductively isolated.
 It’s not all about looks!
Different Species:
They do not
Interbreed,
because they
have different
songs.
Western Medowlark
Eastern Medowlark
What is a species…
 Species definition was made
by humans, and fails to fully
define nature.
 These two ants look
different are the same
species of ant fulfilling
different roles in a colony.
Pheidole barbata
Species definition is not always
black and white
Are we the same?
+
ZONKEY
Photo: Wiki Commons/GNU
Are we the same?
+
LIGER!
Speciation due to isolation
 The islands are close enough
to allow migration and cause
distinct island populations
to arise.
 But the distances between
the islands is great enough
to reduce interbreeding
between islands
 This has made possible the
formation of distinctive
species on the islands
Speciation in grand canyon
Speciation of salamanders due
to geographic isolation
Speciation occurred on the earth over a very long
period of time when the continents slowly drifted apart.
This leads to
geographic isolation
Continental Drift Animation
Process of Natural Selection
 Organisms became isolated on various continents which
restricted interbreeding populations
 Without the opportunity to interbreed and the slowly
changing climatic conditions organisms “evolve” into a
new species over time.
 This leads to “survival of the fittest”
 Fitness: Organisms that are better suited to survive and
reproduce
Discussion Question
 Why does Australia have such strange animals??
Evolutionary Timeline of mammals
Platypus (Monotreme)
Kangaroo (Marsupial)
Dingo (Placental Mammal)